Glycogen content and udpglucose-glucan glucosyl-transferase activity of normal human lymphocytes

Hedeskov, C. J.; Esmann, Viggo; Pérez, María Honrubia

doi:10.1016/0304-4165(66)90235-2

Cited by 26 publications

(5 citation statements)

References 19 publications

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“…A most striking phenomenon is that the enzyme exists to --98% in its b form . A similar coincidence of pronounced glycogen storage with the presence of most of the glycogen synthase activity in its Glc-6-P-dependent form has been reported for human choriocarcinoma cells (21), human (34,36,44) and rat (37) polymorphonuclear leukocytes, human lymphocytes (18), and rat myogenic cells (20) . Surprisingly, the activity of glycogen synthase of HD33 ascites tumor cells resembles closest that of glycogen synthase from the normal human white blood cells.…”

Section: Distribution Of Udpg Pyrophosphorylase In Hd33 Ascites Tumor Cellssupporting

confidence: 79%

Role of nuclear glycogen synthase and cytoplasmic UDP glucose pyrophosphorylase in the biosynthesis of nuclear glycogen in HD33 Ehrlich-Lettré ascites tumor cells.

Granzow¹,

Kopun²,

Zimmermann³

1981

The Journal of Cell Biology

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Biochemical and autoradiographic evidence show both glycogen synthesis and the presence of glycogen synthase (UDP glucose [UDPG] : glycogen 4-a-D-glucosyltransf erase; EC 2.4 .1 .11) in isolated nuclei of Ehrlich-Lettre mouse ascites tumor cells of the mutant subline H D33. 5 d after tumor transplantation, glycogen (average 5-7 pg/cell) is stored mainly in the cell nuclei . The activity of glycogen synthase in isolated nuclei is 14 .5 mU/mg protein. At least half of the total cellular glycogen synthase activity is present in the nuclei . The nuclear glycogen synthase activity exists almost exclusively in its b form . The K,, value for (a + b) glycogen synthase is 1 x 10-3 M UDPG, the activation constant is 5 x 10 -3 M glucose-6-phosphate (Glc-6-P) .Light and electron microscopic autoradiographs of isolated nuclei incubated with UDP-[1-3 H]glucose show the highest activity of glycogen synthesis not only in the periphery of glycogen deposits but also in interchromatin regions unrelated to detectable glycogen particles. Together with earlier findings on nuclear glycogen synthesis in intact HD33 ascites tumor cells (Zimmermann, H .-P., V. Granzow, and C. Granzow. 1976 . J. Ultrastruct. Res. 54 :115-123), the results of tests on isolated nuclei suggest a predominantly appositional mode of nuclear glycogen deposition, without participation of the nuclear membrane system .In intact cells, synthesis of UDPG for nuclear glycogen synthesis depends on the activity of the exclusively cytoplasmic UDPG pyrophosphorylase (UTP : a-D-glucose-1-phosphate uridylyltransferase ; EC 2.7 .7 .9) . However, we conclude that glycogen synthesis is not exclusively a cytoplasmic function and that the mammalian cell nucleus is capable of synthesizing glycogen .Intranuclear glycogen deposition has been observed in amphibian (19), avian (11), and a variety of mammalia cells, particularly in hepatocytes (5,28,30,38), cells of renal collecting tubules (6), and cardiac muscle cells (8), partly under normal, partly under various pathological conditions . With respect to the origin of intranuclear glycogen, translocations of cytoplasmic glycogen particles into the nuclear compartment (30,40) free wild-type Ehrlich-Lettrt; ascites tumor, which was manipulated pharmacologically by means of N-methyl-colchicamide (27). A genome mutation of HD33 cells is associated with various phenotypical deviations from the wild type,' among which a pronounced nuclear and/or cytoplasmic glycogen storage is the most conspicuous (46). Characteristically, between days 4 and 6 after transplantation, glycogen deposits of increasing size are located chiefly within the tumor cell nuclei . Additional cytoplasmic glycogen storage is restricted to later stages oftumor development (46). On days 5 and 6, pronounced nuclear glycogen storage coincides with minimal cytoplasmic glycogen deposition in interphase cells . Thus, cells at this stage of tumor development provide a unique substrate for an analysis of their nuclear glycogen metabolism.In previous communications (...

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Section: Distribution Of Udpg Pyrophosphorylase In Hd33 Ascites Tumor Cellssupporting

confidence: 79%

Role of nuclear glycogen synthase and cytoplasmic UDP glucose pyrophosphorylase in the biosynthesis of nuclear glycogen in HD33 Ehrlich-Lettré ascites tumor cells.

Granzow¹,

Kopun²,

Zimmermann³

1981

The Journal of Cell Biology

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“…The lymphocyte suspensions were contaminated with 2-3 red blood cells and less than 1 platelet/lymphocyte. These contaminations have been shown to be negligible with respect to the extent of glucose utilization and the evaluation of the contribution of various pathways to glucose metabolism (Hedeskov & Esmann, 1966;Hedeskov, Esmann & Rosell Perez, 1966). The differential leucocyte count gave 95% lymphocytes and 5% polymorphonuclear leucocytes.…”

Section: Methodsmentioning

confidence: 99%

“…Radioactivity was assayed in a Tri-Carb liquid-scintillation spectrometer (Packard model 2002). The scintillator was as described by Hedeskov et al (1966). The background count rate was ascertained for each container with scintillator before addition of samples.…”

Section: Methodsmentioning

confidence: 99%

Early effects of phytohaemagglutinin on glucose metabolism of normal human lymphocytes

Hedeskov

1968

Biochemical Journal

106

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1. Phytohaemagglutinin induced early changes in the catabolism of glucose by normal human lymphocytes suspended in a bicarbonate buffer. During 4hr. incubation glucose utilization was almost doubled. 2. The rates of several reactions in the metabolism of glucose were estimated. Total pyruvate formation, lactate production and fatty acid synthesis were stimulated to the same degree as was glucose utilization. The pentose cycle and the glycogen synthesis were also stimulated but less than was glucose utilization. The pentose cycle was found to account for 1.4% and 0.9% of the total glucose utilization without and with phytohaemagglutinin respectively. In these cells rates of triose phosphate iso-merization were at least six to seven times the rate of glucose phosphorylation. On an average 55-60% of the total carbon dioxide evolved was derived from decarboxylation of pyruvate, 25-30% from the tricarboxylic acid cycle and about 15% from the pentose cycle. Observed ratios of (14)C specific yields in glycogen from [1-(14)C]- and [6-(14)C]-glucose could possibly be explained by assuming the existence of two separate glucose 6-phosphate pools. 3. During 4hr. incubation in bicarbonate buffer (14)C from [U-(14)C]serine was incorporated into perchloric acid-insoluble material. This incorporation was stimulated by phytohaemagglutinin but was almost completely inhibited by puromycin. Puromycin also abolished phytohaemagglutinin-induced stimulation of glycolysis.

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“…The interconversion between synthetase-D and synthetase-I, the glucose-6-phosphate-independent form of the enzyme, is readily demonstrated in homogenates of human lymphocytes [58] and normal and alloxan-diabetic rat exudate PMN leukocytes [89], but several investigators have failed to demonstrate a D to I conversion in homogenates of human PMN leukocytes, leading to the conclusion that normal PMN leukocytes lack synthetase-D phosphatase activity [44], Recently, however, Wang et al [113] found that reducing the very high glycogen content of leukocytes by incubating intact cells in a glucose-free bicarbonate buffer was accompanied by a 25% D to I conversion. This might be explained as glycogen having an inhibitory action on the activity of synthetase-D phosphatase similar to that postulated from the study of muscle and liver [20,21].…”

Section: Glycogen Metabolismmentioning

confidence: 99%

The Diabetic Leukocyte

Esmann¹

1972

Enzyme

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The metabolism of polymorphonuclear leukocytes in diabetes is reviewed. The available evidence points towards glucose being freely permeable to the cell membrane. Varying results have been obtained on the rate of glucose utilization and glycolysis, probably due to the different experimental conditions employed by various investigators. In this respect, the crowding effect, i.e. the decrease in metabolic rate observed by increasing the cell concentration, is of special importance. When, however, normal and diabetic cells are incubated in a bicarbonate buffer at the same low cell concentration to avoid the crowding effect, a comparison shows that the glycolysis of diabetic cells is decreased. Glucose-6-phosphate and fructose-6-phosphate accumulate in diabetes, suggesting a decreased activity of phosphofructokinase (EC 2.7.1.11). The increase in glucose-6- phosphate concentration is probably responsible for a small decrease in glucose utilization and a slight increase in pentose cycle activity as well as for an increase in the relative amount of glycogen synthetized. Insulin in vivo corrects the metabolic alterations, whereas there is no convincing evidence of an effect of insulin in physiological concentrations in vitro. The crowding effect has been proposed to be due to an inhibition of the activity of phosphofructokinase by the drop in pH which is caused by the accumulation of lactic acid during the incubation. The absence of the crowding effect in diabetic leukocytes has motivated the suggestion that the sensitivity of phosphofructokinase to changes in pH is compromised in diabetes. The amount of glycogen and its synthesis is markedly reduced in diabetes. The total activity of glycogen synthetase, as well as the ability for D to I transformation, is decreased in diabetic cells and normalized by insulin in vivo, no discernible effect of insulin in vitro being present. The respiration of diabetic leukocytes is normal. No conclusive information on lipid or protein metabolism in diabetic leukocytes is available. The function of leukocytes in inflammation appears to be hampered, but no definite corollary to the impaired carbohydrate metabolism has been produced.

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Glycogen content and udpglucose-glucan glucosyl-transferase activity of normal human lymphocytes

Cited by 26 publications

References 19 publications

Role of nuclear glycogen synthase and cytoplasmic UDP glucose pyrophosphorylase in the biosynthesis of nuclear glycogen in HD33 Ehrlich-Lettré ascites tumor cells.

Role of nuclear glycogen synthase and cytoplasmic UDP glucose pyrophosphorylase in the biosynthesis of nuclear glycogen in HD33 Ehrlich-Lettré ascites tumor cells.

Early effects of phytohaemagglutinin on glucose metabolism of normal human lymphocytes

The Diabetic Leukocyte

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